Tuning the selectivity and improving the activity of photocatalysts are among the main bottlenecks for the conversion of CO2 to value-added chemicals. Recently, lead-free halide perovskites have been extensively investigated as photocatalysts for the photoreduction of CO2. Herein, we report a composite photocatalyst using Cs3Bi2Cl9 and Ir/IrOx for the photoreduction of CO2. The hybrid photocatalyst Cs3Bi2Cl9-Ir/IrOx displayed a high selectivity towards HCOOH formation with a yield of 158 ± 9 μmol g-1 h-1, suppressing the formation of carbon monoxide. This is the highest yield of HCOOH reported for this class of materials. In this work, we discuss the effective strategy of combining halide perovskites with simple iridium-based catalysts for enhanced and selective photoreduction of CO2 to HCOOH.